The aim of the study is to confirm, whether the MER® stent can be used, without limitations, for the endovascular carotid stenosis treatment in daily clinical practice. Eligible patients will undergo the procedure of the common or internal carotid artery stenting using MER® with proximal or distal neuroprotection.

MER® stent will be implanted in eligible patients with common and internal carotid stenosis after an informed consent.

Potential benefit of the MER® stent implantation will be evaluated based on angiography and duplex Doppler ultrasound examination.

Follow ups are scheduled at 30 days, 6 and 12 months after index procedure. Except for clinical follow up patients will undergo carotid vessels ultrasound examination after 6 and 12 months. In case of an emergency visit, caused by the Serious Adverse Event, Patient will undergo: neurological and cardiac evaluation as well as carotid vessels USG examination and extended CT or MRI scans.

In general, all procedures in the study will follow the local standard of care. The type of devices used during the angioplasty (including the MER® stents) will not differ from the devices used in the usual clinical practice in the hospital. DAPT and other medical therapy will be consistent with the rules of the Polish and European Society of Cardiology.

Inclusion Criteria:

• De novo lesion located in the internal carotid artery or common carotid artery

  • DS ≥50% (nonsymptomatic patients) and ≤99% based on QCA
  • DS ≥75% (symptomatic patients) and ≤99% based on QCA

• Target lesion available for 20-60mm lenght and 4-10mm diameter scaffold

• Patient eligible for CAS

• Age ≥ 18

• Life expentancy ≥ 12 months

• The patient's written informed consent has been obtained prior to the procedure.

Exclusion Criteria:

• Lack of neurological CAS qualification
• The patient has experienced an acute myocardial infarction within 72 hours of the procedure
• The patient has known paroxysmal, persistent or permanent atrial fibrillation or flutter
• The patient has known gastrointestinal bleeding
• Pregnancy
• DAPT contraindications
• Surgery planned within 1 month after the procedure
• A platelet count <100,000/mm³ or >600,000/mm³
• The patient has known nickel, titanium or contrast allergy
• The target vessel is totally occluded
• The patient has stent(s) in the target lesion
• Statin therapy contraindications
• The target lesion has massive calcifications
• Hyperthyroidism
• Post-radiotherapy side effects
• No pulse in femoral artery
• Chronic kidney disease (creatinine level >2,0 mg/dl or eGFR<30 mL/min/1.73 m2 or dialysotherapy)